Notched IC Package Heat Sink for Delamination Relief
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Solution Overview
Problem
Conventional heat sinks in integrated circuit packages face mechanical stresses due to thermal expansion differences between materials, leading to delamination and degraded thermal performance, which can cause overheating and render the integrated circuit unusable.
Innovation Solution
The heat sink design features open notches forming fins separated by notches, radial, and peripheral notches to reduce mechanical stresses, along with a ribbed surface with grooves to enhance attachment and reduce delamination, allowing for thermal interface material deformation and improved heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional heat sinks are used with solid mounting areas, then heat dissipation is achieved, but mechanical stresses from thermal expansion differences cause delamination at the interface
Solution Approach 1:
The mounting area is segmented into multiple fins separated by open notches, transforming the solid mounting area into a structured array. This segmentation allows thermal interface material to be applied to multiple fin surfaces, increasing the effective heat dissipation area while the notches provide stress relief zones that prevent delamination during thermal cycling.
2Strength
If the heat sink is made as a single solid piece, then structural strength is maintained, but thermal expansion stresses cannot be relieved causing delamination
Solution Approach 1:
The heat sink mounting area is divided into multiple fins with open notches between them, creating independent stress zones. Each fin can expand and contract independently during thermal cycling, relieving mechanical stresses that would otherwise accumulate in a solid structure and cause delamination at the interface.
3Strength
If thermal interface material is applied to a solid mounting area, then attachment is achieved, but stress concentration occurs at corners leading to delamination
Solution Approach 1:
The mounting area is segmented into fins separated by notches, distributing the thermal interface material across multiple surfaces rather than one continuous solid area. This segmentation reduces stress concentration at corners by creating discrete attachment zones, allowing the interface to better accommodate thermal expansion differences.
4Loss of energy
If the heat sink mounting area is increased to improve heat dissipation, then thermal performance improves, but mechanical stresses increase leading to higher delamination risk
Solution Approach 1:
The mounting area is organized into multiple fins with open notches, increasing the effective surface area for heat dissipation through the fin structure. The notches between fins create stress relief zones that prevent mechanical stress accumulation, allowing the heat sink to achieve improved thermal performance without proportionally increasing mechanical stress and delamination risk.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design significantly reduces mechanical stresses and the risk of delamination, maintaining effective heat dissipation and thermal performance by allowing for thermal expansion differences and enhancing attachment between the heat sink and chip.
Implementation Method 1
the heatsink is bonded on the chip with a thermally conductive material allowing the heat to be transferred from the chip to the heat sink
Implementation Method 2
Heat sinks are used to dissipate to the outside of the package the heat produced by the chip of an integrated circuit during its operation
Implementation Method 3
the heat produced by the annealing steps during the manufacture of the package, or by the electronic chip, causes expansion of the heat sink and of the chip
Data Source
AI summary
An integrated circuit includes an electronic chip having a face covered with a thermal interface material layer. A heat sink includes a mounting area fixed to the chip via the thermal interface material layer. The heat sink includes open notches extending into the mounting area to delimit fins separated from each other by the open notches.